A framework on how the inter-domain communications need to be done in H.323 for mobility management has been provided in the context of the existing H.225.0 Annex G standard, as disclosed in ITU-T Recommendation H.225.0 Annex G (1999), “Communications Between Administrative Domains”. The communication flows for mobility management considering the BE (Border Elements), Gatekeepers (GKs), Home location function (HLFs), and domains where each entity can be arranged in any logical architectural relationship: Centralized, Distributed, and/or Hybrid Architecture. ITU-T Recommendation H.323 describes terminals and other entities that provide multimedia communications services over packet based networks (PBN) which may not provide a guaranteed Quality of Service. H.323 entities may provide real-time audio, video and/or data communications. Support for audio is mandatory, while data and video are optional, but if supported, the ability to use a specified common mode of operation is required, so that all terminals supporting that media type can interwork.
The inter-domain mobility management of this invention needs to be independent of the underlying architectural configurations and is not “hard-wired” for any particular configuration of any architectural or functional entity as done in the prior art.
The new messages for mobility management within a domain has been proposed for H.225.0 RAS (Intra-domain communication) messages. Similarly, for inter-domain mobility management we need to extend H.225.0 Annex G, as disclosed in ITU-T Recommendation H.225.0 Annex G (1999), “Communications Between Administrative Domains.” The new messages, such as, disclosed in R. R. Roy, AT&T, “H.323 Mobility Architecture and Protocol for Terminal, User, and Service Mobility,” D-354, ITU-T SG 16 Q.13/16, WP2, Geneva, Switzerland, Feb. 7-18, 2000, the disclosure of which is entirely incorporated herein by reference, required for mobility binding and updating will also be applicable for inter-domain communication with additional parameters like hopcounts and others in the header as required per H.225.0 Annex G.
In addition, the existing H.225.0 RAS messages like LRQ (Location Request) such as, disclosed in R. R. Roy, AT&T, “H.323 Mobility Management Services, Scenarios, and Information Flows in an Administrative Domain,” MD012, Ad Hoc Mobility Conference Call, February-May 2000, have been extended to manage mobility for intra-domain communications. Similarly, the messages like accessRequest and others of H.225.0 Annex G are also need to be extended for inter-domain mobility management as described in this embodiment. However, the mobility related parameters that specify the information related to the mobile entity used in the LRQ and call signaling messages of H.225.0 RAS/Q.931 also need to be passed to the accessRequest and other messages of H.225.0 Annex G while the mobile entity is visiting a foreign domain.
It is also the critical need for a mobile entity to have an option whether it will let others to know its present location in a foreign domain because of security or other reasons while it is away from its home domain. If the mobile entity does not want to make its address public while it is visiting in a foreign domain, the communications need to be done via mobile entity's home network address that it may want make to public.
Originally, the International Telecommunications Union (ITU) developed H.323 as an adaptation of H.320, which addresses videoconferencing over ISDN and other circuit-switched networks and services. ITU-T Recommendation H.320 describes terminals and other entities that provide multimedia communications services over circuit-switched networks which provide a guaranteed Quality of Service. H.320 entities may provide real-time audio, video and/or data communications. H.320 was ratified in 1990, and corporations expanded their networks to include Local Area Networks (LANs) and LAN gateways to the Wide Area Network (WAN). Then, H.323 was expanded beyond being an extension of H.320 so that H.323 now covers the corporate intranets and packet-switched networks in general. The ITU published a set of standards for multimedia communication over packet-based networks (PBNs) under the H.323 designation, which includes standards for data channels, monitoring channels, and control channels. It includes provision of real-time audio, video and/or data communications. The H.323 components defined by the standard include: terminals, gateways, gatekeepers and multipoint control units (MCUs). The terminals provide real-time communications, must support audio/voice communications and optionally s support data and video. The most common H.323 terminals are the applications that run on a personal computer (PC). H.323 gateways provide services to H.323 clients and allow communication with non-H.323 entities, such as communication between H.323 terminals and telephone in a circuit-switched network. Gatekeepers provide call control services for H.323 endpoints, e.g., address translation and bandwidth management. Gatekeepers are optional in the H.323 standard, but, if they are present, the endpoints must use the services of the gatekeepers. The H.323 standard specifies certain mandatory services that gatekeepers, if utilized, must provide. The multipoint control units provide support for conferences of three or more endpoints by managing conference resources, manage negotiations between the endpoints to specify which audio or video code(s) to use and may manage the media stream. The H.323 standard defines how audio and video conferencing systems communicate over packet-switched networks defines call control and management practices for point-to-point and broadcast/multicast/unicast multipoint conferences, addresses QoS issues with a centralized gatekeeper that LAN administrators use to manage media traffic, bandwidth and user participation, and describes functionality that allows calls to connect from the LAN to the Public Switched Telephone Network (PST) as well as to other H.32×standards-based terminals.
In version 2 of the H.323 standard, video and audio data streams are compressed and packetized in accordance with a real-time transport protocol (RTP/RTCP) standard from the Internet Engineering Task Force (IETF) and are used to support video conferencing and other communications over the Internet. Packets include data and header information which facilitates detection of packet loss, detection of packet status and synchronization of the packets. The video data streams may use H.261, H.262, or H.263 protocols. Audio data streams may use G.711, G.722, G.723.1 G.728 or G.729 protocols. Generally, the H.323 standard supports teleconferencing in networks that utilize TCP/IP, such as, for example, the Internet.
The H.323 system supports interoperability and assumes that users, terminals, and services are fixed. If an H.323 terminal is moved form one network to another, its point of attachment or network address changes. In this situation, the address of the mobile terminal needs to be resolved to set up a new call or continue a same call. Thus, there is a need for an H.323 mobility architecture that provides for terminal, user and service mobility for inter-domain mobility management.